Power transmission with modulating torque converter input clutch

Abstract

A power transmission mechanism includes a hydrokinetic torque converter driven by a hydraulically actuated modulating friction clutch having a piston disposed in and sealingly engaged with the converter housing to form opposed fluid chambers. Fluid in the torque converter housing flows through an orifice between the chambers and exits the converter housing by way of a flow control valve. A pressure differential is imposed on the piston by controlling the outflow of fluid from one of the chambers to modulate clutch engagement for varying the power output of the torque converter.

What is claimed is: 
     
       1. A transmission mechanism comprising a rotatable housing connected to a driving member; a movable piston disposed in said housing and dividing the interior of said housing into first and second fluid chambers;   a hydrokinetic coupling disposed in said first chamber and including rotatable impeller and turbine members;   a clutch disposed in said second chamber and including driving and driven members operable to be selectively engaged to drivingly connect said housing to said impeller in response to movement of said piston;   restricted passage means interconnecting said first and second chambers;   a fluid circuit including means for causing pressure fluid to flow through said first and second chambers by way of said passage means, first conduit means for conducting fluid to said first chamber, second conduit means for conducting fluid from said second chamber, a control valve for throttling the flow of fluid from said second chamber to cause a selectively variable pressure difference between said chambers for actuating said piston to modulate the engagement of said clutch, and further conduit means interconnecting said first conduit means and said control valve, said control valve being operable to conduct fluid to said second conduit means from said first conduit means without flowing through said first and second chambers when the flow of fluid from said second chamber is substantially throttled.   
     
     
       2. A transmission mechanism comprising a rotatable housing connected to a driving member; a movable piston disposed in said housing and dividing the interior of said housing into first and second fluid chambers;   a hydrokinetic coupling disposed in said first chamber and including rotatable impeller and turbine members;   a clutch disposed in said second chamber and including driving and driven members operable to be selectively engaged to drivingly connect said housing to said impeller in response to movement of said piston, said driving and driven members including coactable friction surfaces thereon, said housing including a removable cover member having a driving friction surface thereon;   restricted passage means interconnecting said first and second chambers and a fluid circuit including means for causing pressure fluid to flow through said first and second chambers by way of said passage means, said passage means being disposed to be in communication with said second chamber in such a way that at least a portion of the fluid flowing through said second chamber flows over said friction surfaces; and,   a control valve for controlling the flow of fluid to cause a selectively variable pressure difference between said chambers for actuating said piston to modulate the engagement of said clutch.   
     
     
       3. The invention set forth in claim 2 wherein: said driven member of said clutch comprises at least one friction plate drivingly connected to said impeller, said driving member of said clutch includes a friction surface of said piston drivingly engageable with said plate, and said plate is disposed in said housing between said piston and said cover member.